package com.hi.hiparty.util;

import java.math.BigDecimal;

public class LocationUtil {

	private static final double EARTH_RADIUS = 6378.137;

	private static double rad(double d) {
		return d * Math.PI / 180.0;
	}

	public static double GetDistance(double lat1, double lng1, double lat2, double lng2) {
		double radLat1 = rad(lat1);
		double radLat2 = rad(lat2);
		double a = radLat1 - radLat2;
		double b = rad(lng1) - rad(lng2);
		double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2)
				* Math.pow(Math.sin(b / 2), 2)));
		s = s * EARTH_RADIUS;
		s = new BigDecimal(s).setScale(1, BigDecimal.ROUND_HALF_UP).doubleValue();
		return s;
	}

	public static void main(String[] args) {
		System.out.println(GetDistance(39.984917, 116.339819, 39.968598, 116.401416));
	}

}
